Box making die



July 9, 1957 E. c. CLEMENT 2,798,416

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`Iuly 9, 1957 E C, CLEMENT 2,798,416

BOX MAKING DIE United States PatentO BOX MAKING DIE Ernest C. Clement,Oak Park, lll.

Application April 19, 1954, Serial No. 424,149

2 Claims. (Cl. 93-51) This invention relates to a die for making boxesof cardboard or like material, and more particularly to a die which iscapable of quick and easy adjustment for boxes of different sizes.

One important object of 'the invention is to provide a box making diewhich avoids the use of change parts for boxes of different sizes. Apartfrom simple, continuously variable adjustments of the die itself, theonly element necessary for making a box of a particular size is aplunger having an exterior shape and size corresponding with theinterior shape and size of the desired box. This plunger is ofinexpensive construction and quickly and easily installed in a machineutilizing the die ofthe invention.

Another object of the invention is to provide a die capable offabricating a box having double layer end walls, although the die isequally eective to form a box having single layer end walls.

Another object of the invention is to provide a box making die capableof an extremely high rate of production. This high productivity rate ismade possible because the moving parts of the die exert an extremelyhigh pressure on those portions of the box which are secured together byadhesive. As is well known, proper setting of the adhesive used is afunction of both time and amount of applied pressure. Thus with pressureof maximum amount, as provided by the invention, the time required forapplication of the pressure is minimized with the result that theproductivity rate of the die may be extremely high..

Another object of fthe invention is to provide a box making die of suchconstruction that mechanical failure is not likely to occur in the eventthat two or more box blanks simultaneously are fed into the die. Priordies of this general character have marginal castings or framework whichare stressed as a result of the adhesive-setting pressure applied to thebox by the movingparts of the die, and this marginal casting orframework is highly subject to failure when two or more box blanksaccidentally enter the die. The present die does not have castings orframework members which are subject to such stresses.

Sltill another object of the invention is to provide a box making diewherein the amount of adhesive-setting pressure applied to a box by thedie may be varied while the machine in whch the die is used continues inoperation. In other words, it is unnecessary to stop the machine inorder to make an adjustment which will increase or decrease the pressureapplied by the movable die parts.

Still another object of the invention is to provide a box making diewhich utilizes more or less the same structural elements for the dualfunction of adjusting the distance between the movable parts of the dieand for moving these parts under substantial pressure to set theadhesive used in the box ends.

Another object of the invention is to provide a box making die which isa self-contained unit, that is, a unit which bears a sub-assemblyrelationship to the box mak- Patented July 9, 1957 ing machine in whichthe die is incorporated. Thus the die with all its adjustabilityfeatures etc. may be fabricated apart from the machine and easilyinstalled therein.

Other objects, advantages and details of the invention will be apparentas the description proceeds, reference being had to the accompanyingdrawings wherein one form of the invention is shown. llt is to beunderstood, however, that the description and drawings are illustrativeonly and that the scope of the invention is to be measured by theappended claims.

In the drawings:

Fig. 1 is a top plan view of a box making die embodying this invention,certain cooperating structure being shown in dotted lines;

Fig. 2 is a sectional view on line 2 2 of Fig. 1;

Fig. 3 is a sectional view on line 3-3 of Fig. l;

Fig. 4 is an enlarged sectional view on a portion of line 2-2 of Fig. l;

Fig. 5 is an enlarged sectional view on line 5 5 of Fig. l;

Fig. 6 is a front elevational View of the elements shown in Fig. 5;

Fig. 7 is a top plan view of a box blank usable in the die of theinvention, and

Fig. 8 is an elevational view, partly in section, on line S-S of Fig. l,showing a toggle-joint forming part of the invention.

Following is a detailed description of the illustrated embodiment of theinvention:

BOX BLANK As previously mentioned, the present die is capable of makingboxes of cardboard or the like which have either single or double layerside and/or end walls. Double layer walls, of course, provide strength,and thus enable the use of somewhat lighter stock for the same strengththan is required for boxes having single layer walls. This invention, itis believed, will find its greatest use in the manufacture of boxeshaving both double layer side walls and double layer end walls.

A blank 18 for such a box, suitable for use in the invention, is shownin Fig. 7. The central blank portion 20 constitutes the box bottom, theportions 21 constitute one layer of the two side walls and the portions22 constitute lthe other layer of the side walls.

The side wall portions 21 and 22 are provided with suitable adhesive andportion 22 is folded over, as shown, and pressed into securingengagement with the portion 21 by conventional means before the blankreaches the die. Thus, the present die is not concerned with theformation of the double layer side walls, and, as mentioned above, useof same is optional.

At each end vof side wall portions 21 is a tab 24 which is foldablealong a scored line of attachment 25 with portion 21 to an ultimateposition at right angles to the portion 21. The die is effective toproduce the required folding of tabs 24, this folding being initiatedjust prior to the folding of the following described box end walls.

The end walls comprise portions 26 which are contiguous to bottom 20and, in the case of double end walls, portions 27.

Before a box blank 18 reaches the present die, suitable adhesive isapplied by conventional means to the blank ron predetermined areas suchas those designated by 28 which embrace areas of broth portions 26 and27 of the end walls.

GENERAL OPERATION OF THE DIE.

position with respect to the present die, the blank lying in ahorizontal plane on the top of the die. A vertically movable plunger,later to be described in detail, having external dimensions whichcorrespond generally with the internal dimensions of the box underconstruction. descends into engagement with bottom portion 2li of theblank. As bottom portion and the remaining portions of the blank arepushed downwardly by contin-ued movement of the plunger, corner controlelements of the die are effective to start the folding of corner tabs 24before the folding 'of the other blank portions commences. This insuresthat tabs 24 ultimately will have proper relation with the end wallportions 26 and 27.

As the plunger continues its downward stroke, tabs 24 continue to befolded with respect to side wall portions 21. At the same time side wallportions 21 and end wall portions 26 are folded along their scored linescommon with bottom portion 20 until they assume a generally right anglerelationship with bottom portion 20. When this relationship is reachedthe tabs 24 are at right angles to adjoined portions 21 and are tiushagainst inside surfaces of the upturned 'end portions 26.

In practice, the die may be constructed so that side wall portions 21are folded through an angle which exceeds 90 degrees by a small amountso that following inherent spring back the final wall will have a moreexact 90 degree relation with the box bottom.

When the plunger reaches its lowermost stroke position, bottom portion20 of the blank is disposed in a plane defined by a plurality of suctionmeans, later to be described, which are energized to retain bottomportion 20 in said plane. The plunger then is caused to m'ove upwardlyand out 'of the partially formed box, the latter being stripped from theplunger by reason of the suction means which holds 'the box against:upward movement.

When the plunger is free of the partially formed box, a plurality of endwall tucking fingers function to fold end wall portions 27 inwardly andbring them into engagement with inner surfaces of the tabs 24 andportions 26 where they are held momentarily by the previously appliedadhesive of areas 28. The tucking fingers thereafter are withdrawn andthe plunger immediately moves downwardly into the partially formed box.

When the plunger reaches its lowermost position, movable portions of thedie, namely front and rear pressure plates which lie adjacent the endwalls `of the box, travel toward the plunger under extremely highpressure. This, of course, applies severe ,pressure to the end walls ofthe box, and the pressure is effective to set the adhesive in anextremely short period of time.

Thereafter, the movable portions of the die (pressure plates) moveapart, the suction means are deenergized and the plunger travelsupwardly carrying with it the n'ow completely formed box. When theplunger and box clear the die, the succeeding box blank 18 is moved intoposition on the die. Thereafter a stripper removes the completed boxfrom the plunger, the box dropping to the upper surface of thesucceeding box blank. A suitable sweeper then functions to eject thecompleted box from the vicinity of the die and the above describedsequence is repeated with the succeeding blank 13 then in position onthe die.

CONSTRUCTION OF THE DIE (a) basic structure Referring now to Figs. l-6of the drawings, a die embodying this invention includes a supportingframework 30. This framework, illustrated as a simple rectangle made upof angle irons, may be as shown or it may consist of a more or lessequivalent framework which is a part lof the more extensive framework ofthe entire machine of which the present die is a part. The present die,as will be seen, has lonly a few structural connections withsupportingfralrnework Y30; therefore the die proper may be constructedas a self-contained unit regardless of whether a separate framework 30is provided or the framework 30 is a part of the framework of the entiremachine. In either case, the die proper has a sub-assembly relationshipto the entire machine.

Since the direction of box blank feed through the die is from right toleft, looking at Fig. l, the right 4hand portion of Fig. l will bereferred to as the rear of the die and the left hand portion will bereferred to as the front 'of the die. Also, the term longitudinal willrefer to the direction between the front and the rear of the die whilethe term transverse will refer to the direction at right angles theretoor between the two sides of the die.

A feature of basic importance in a die embodying this invention is theprovision of screw means which extends longitudinally of and arej'ournalled on framework 30. In the form of the invention shown thisimportant screw means feature comprises a pair of laterally spaced mainshafts 33 and 34 which extend between the front and rear ends offramework 30 and which are journalled for rotation with respect to theframework. Thus, each shaft end is journalled for rotation in a bearingor pillow block 36 which is suitably secured as by bolts to framework30. Bearing or pillow blocks 36 preferably are 'of the self-alignmenttype so as to avoid alignment problems and excessive, rigid structureotherwise necessary to maintain proper alignment.

Main shafts 33 and 34, as will be seen, have dual functions. Theycooperate both to provide adjustment for different box lengths and toapply adhesive-setting pressure to the box ends.

Main shaft 33 has its opposite end portions provided with threads ofopposite hand, e. g. the left hand portion may have right hand threads37 in which case the right end portion would have left hand threads 38.Similarly, main shaft 34 has its opposite end portions provided withthreads of opposite hand. While it is possible to thread correspondingends of the two shafts with threads of the same hand, it is preferred tothread such corresponding ends with threads of opposite hand, in whichcase the left end portion of main shaft 34 is provided with left handthreads 39 and the right end is provided with right hand threads 4t).This relationship of threads, as will be seen, enables the use of andthe mechanical benefits provided by a toggle-joint arrangement forrotating the main shafts 33 and 34 in connection with the pressureapplying function of the shafts.

Each end portion of each main shaft 33 and 34 is provided with a nutwhich is threaded internally to cooperate with the threads of itsassociated end portion. Thus, referring to Fig. l, main shaft 33 has nut43 threaded on its left end portion and nutV 44 threaded on its rightend portion. Similarly, main shaft 34 has nut 45 threaded on its leftend portion and nut 46 threaded on its right end portion.

Nuts 45 and 46 on main shaft 34 have an exterior portion comprising spurgears 47 and 48, respectively. As shown, spur gears 47 and 48 areintegral with nuts 45 and 46 but other equivalent arrangements may beused.

Nuts 43 and 44 on main shaft 33 have associated sprockets 49 and S0, thesprocket 49 being best shown at the left in Fig. 3.

The various nuts 43, 44, 45 and 46 and their associated spur gears andsprockets are elements which, like main shafts 33 and 34, have dualfunctions. As will be seen,

they cooperate both to provide adjustment for ditferentY box lengths andto apply adhesive-setting pressure to the box ends.

Nuts 43, 44, 45 and 46 are ganged together to rotate in synchronism insuch direction that the two left nuts (Fig. 1) move in one directionwhen the two right nuts move in the opposite direction. This movement ofthe nuts, responsive to nut rotation, is relied on to adjustV the diefor different box lengths. The illustrated means `forjrotating the'nutsin proper synchronism will now be described. This means also iseffective, when not used to rotate the nuts, to restrain the nutsagainst rotation when the main shafts 33-34 are rotated in connectionwith the pressure applying function of the die.

(b) Remaining elements providing box length adjustment Referring toFigs. 2 and 3, an adjusting countershaft is disposed directly below eachof the main shafts 33 and 34, the countershafts being suitablyjournalled in framework 30, as best shown in Fig. 2. Thus, adjustingcountershaft 53 is disposed in spaced relation below main shaft 43 andadjusting countershaft 54 is similarly disposed below main shaft 34.

Referring to adjusting countershaft 54, best shown in Fig. 2, spur gears55 and 56 are splined thereto in such positions as to mesh with gears 47and 48, respectively. Thus, gears 55 and 56 are slidable alongcountershaft 54 by virtue of the splined relationship. With thisarrangement, rotation of countershaft 54 by, for example, a crankapplied to left end 58 causes nuts 45 and 46 to rotate in the samedirection, a direction which, incidentally, is opposite to that of thecountershaft rotation. Due to the threads of opposite hand on the twoend portions of main shaft 34, when the nuts 45 and 46 are rotated inone direction they move toward one another and when rotated in theopposite direction they move away from one another.

Still referring to Fig. 2, spur gears 55 and 56 have associatedsprockets 57 and 58, respectively. The sprocket 57 also is well shown inFig. 3 at the right.

Adjusting countershaft 53 has take-up sprockets 60 (Fig. 3 at left)splined thereto, one at each end below the sprockets 49 and 50associated with main shaft nuts 43 and 44. Thus sprockets 60 areslidable longitudinally of countershaft 53.

Referring to Fig. 3, an endless chain 62 passes around sprocket 57 atthe right, sprocket 49 at the left and takeup sprocket 60 at the left. Asimilar endless chain 63 (Fig. 1 at right) passes around sprocket 58 oncountershaft 54, sprocket 50 on nut 44 of main shaft 33 and thesub-adjacent take-up sprocket 60 (not shown).

With this arrangement, when countershaft 54 is rotated by a crankapplied to front end 58 in, for example, clockwise direction, asindicated by arrow 65, the chain will travel and the various sprockets57, 60 and 49 will rotate in the directions indicated by the otherarrows applied to Fig. 3. Thus, main shaft nuts 43 and 45 will rotate alike amount in opposite direction and, due to threads 37 and 39 ofopposite hand on corresponding ends of main shafts 33 and 34, the nuts43 and 45 will travel longitudinally of main shafts 33 and 34 throughcorresponding distances in like direction.

Similarly, nuts 44 and 46 at the opposite ends of main shafts 33 and 34will travel longitudinally of the shafts through corresponding distancesand in like direction, the travel direction of the latter nuts beingopposite to that of nuts 43 and 45. This equal and opposite travel ofthe nuts at the two ends of main shafts 33 and 34 provides adjustmentsfor boxes of different lengths, as will be seen.

The respective nuts 43, 44, 45 and 46 engage backup blocks 73, 74, 75and 76 (Fig. l). As more clearly shown in Figs. 2 and 4, the back-upblocks are provided with apertures havino internal bearing elements.Backup block 75, for example, is mounted on main shaft 34 andsub-adjacent countershaft 54, the two shafts passing through theapertures and associated bearings. Thus, back-up block 75 is slidablealong the two shafts and, as will be seen, its longitudinal movement isthe same as that of associated main shaft nut 45. The other backupblocks are similarly constructed and similarly mounted on their relatedtwo shafts in association with their cooperating main shaft nuts.

A front pressure plate 80 is carried by the two backup blocks 73 and 75,the plate extending transversely of the die. Similarly, a rear pressureplate 81 is carried by back-up blocks 74 and 76, this pressure platealso extending transversely of the die and in parallelism with frontpressure plate Stb. As shown in Figs. 2 and 4, pressure plates and 81have a substantial vertical dimension which enables them to accommodateboxes of different predetermined heights. The two plates are suitablyapertured as shown in Fig. 2 to pass the main shafts 33-34 and thecountershafts 53-54.

The longitudinal spacing of pressure plates 80 and 81 is adjusted by theadjusting arrangement described above, and, generally speaking, theadjusted distance between the plates determines the length of the boxformed by the die. It will be seen from the relative lengths of mainshaft threads 37, 38, 39 and 40 in Figs. l and 2 that the die is capableof adjustment for boxes of wide- 1y different lengths and that no changeparts, other than the simple plunger previously referred to, arenecessary for conditioning the die for these different lengths.

As previously mentioned, the aforesaid adjusting arrangement also iseffective to restrain the nuts against rotation when the main shafts33--34 are rotated, as will be seen, in connection with moving thepressure plate under adhesive-setting pressure.

(c) Elements providing box width adjustment Referring to Figs. 1 and 3,the back-up blocks 73 and 75 respectively carry side plates 84 and 85. Atransversely extending front side guide adjusting screw 86 has its endsjournalled in side plates 84 and 85. Similarly, back-up blocks 74 and 76have side plates 88 and 89 in which are journalled the ends of a rearside guide adjusting screw 90.

Front and rear side guide adjusting screws 86 and 90 each have oppositeend portions threaded with threads of opposite hand. Corresponding endportions of the two adjusting screws have threads of like hand.

Each end portion of the side guide adjusting screws 86 and 90 carries anut 92 (best shown in Figs. 2 and 4) having appropriate threads for thescrew threads it engages. These nuts, as will be seen, are held againstrotation, and, accordingly, the two nuts on each screw travel toward oraway from each other depending on the direction the screw is turned.

A pair of side guide shafts 93 and 94 extend longitudinally of the die.The ends of shaft 93 are slidably carried and keyed within the nuts 92(Fig. l) associated with like end portions of screws 86 and 90 while theends of shaft 94 are slidably carried and keyed within the nuts 92 onthe opposite end portions of screws 86 and 90.

The side guide shafts 93 and 94 each carry a plurality of downwardlyextending guides 98, there being six such guides 98 illustrated in Figs.1 and 2. A guidel 98 has a hub slidably carried on a shaft 93 or 94 anda downwardly extending, more or less flexible portion 99. Set screws orthe like are provided in the guides 98 to secure the guides to theirassociated shafts and enable the guides to be moved closer together orfarther apart depending on the requirements of box length.

The general relationship between depending portions 99 of the guides andthe horizontal is a right angle but the inwardly facing surfaces of thedepending portions 99 may be contoured in a convex manner to cooperatewith matching contours of the plunger sides so as to fold the box sidesthrough an angle slightly in excess of 90 degrees, thereby providing amargin so that the box sides will be more or less exactly 90 degreeswith respect to the box bottom following the inherent spring back of thematerial.

As shown in Fig. 2, depending portions 99 of the guides have asubstantial vertical dimension to accommodate a reasonable range of boxheights, the vertical dimension being comparable to the correspondingdimension of pressure plates 80 and 81.

infinie Side guide adjusting screws 86 and 90 are ganged together forsynchronous rotation in like direction by means of a side guideadjusting shaft 104 (located near the bottom of Fig. 1). This shaft 104has its ends journalled for rotation in upstanding plates 105 and 106mounted onv framework 30. Left end 107 of shaft 104 is adapted toreceive a crank (not shown) for rotating the shaft in either direction.

Shaft 104 extends through aligned apertures in lateral extensions 10S(Figs. l and 3) of pressure plates 80 and 81. j

The lateral extensions 108 each carry a longitudinally extending plate110 (Fig. 1). Plates 110, in turn, carry transversely extending plates111 which are provided with apertures through which pass adjusting shaft104, main shaft 34 and countershaft 54. Transverse plates 111 and theirrelationship with shafts 34 and 54 are well shown in Fig. 2. Thesetransversely extending plates 111, in addition to cooperating with thepresently to be described side guide adjustment assembly, also cooperateto provide proper relationship between nuts and 46 and associatedback-up blocks 75 and 76. Thus, when nuts 45 and 46 travel toward theends of main shaft 34 they carry with them the transversely extendingplates 111 which, in turn, are connected by longitudinally extendingplates 110 and extensions 108 to the pressure plates and S1. Since thepressure plates 80 and 81 are secured to back-up blocks 75 and 76respectively, the latter likewise move toward the ends of main shaft 34.

A helical gear 115 (Fig. 1) is splined on each end portion of side guideadjusting shaft 104, the helical gears 115 being longitudinally disposedon shaft 104 in the respective regions between pressure plate extensions10S and their associated transversely extending plates 111. Helicalgears 115 are iixed on said shaft in sub-adjacent relation with the endsof side guide adjusting screws 86 and 90 by means of sleeves 116 and 117which respectively extend between each helical gear and the adjacentextension 108 and the adjacent transversely extending plate 111. Thus,as a pressure plate extension 108 and its associated transverselyextending plate 111 travel along adjusting shaft 104, the helical gear115 between the two plates will travel in its spline along adjustingshaft L 104, this latter travel being assured by sleeves 116 and 117.

The side guide adjusting screws 86 and 90 each carry a helical ,gear 120which meshes with one of the helical gears 115 splined to side guideadjusting shaft 104. Thus,

when adjusting shaft 104 is rotated by a crank applied to end 107, thepairs of helical gears 115 and 120 Iare effective to rotate side guide`adjusting screws 86 and 90 in synchronism, thereby moving the sideguides 93 toward or away from each other.

Each nut 92 on the end portions of side guide adjusting screws 86 and 90is capped by a corner tab co-ntrol block 125. These corner tab controlblocks also are well illustrated in Figs. 2 and 4. These blocksfunction, as previously mentioned, to initiated and complete the foldingof the tabs 24 of the box blank 1S.

(d) Elements for forming double layer end walls In order to form doublelayer end walls the box blank portions 27 must be folded through 180degrees to overlie the folded corner tabs 24 of the blank. This foldingoperation is accomplished, as previously mentioned, after the side wallportions 21 `and the first layer portions 26 of the end walls have beenfolded to a position at right angles to the box bottom 20. At this timethe plunger moves upwardly and out of the partially formed box.

When the plunger is clear of the box end wall, tucking fingers (Fig. 5)adjacent each box end move from the dotted line position to the fullline position and fold in the box blank portions 27 to form the secondlayer of the double layer end wall. Immediately vafter reaching the fullline position in Fig. 5, iingers 130 return to the dotted line positionso the plunger may again enter the box. Thus, fingers 130 oscillatebetween their two limiting positions.

Tucking fingers 130 are secured to a pair of transversely extendingfinger shafts and 136, best shown in Fig. l. Finger shaft 135 has itsends journalled in side plates 34 and 85, and finger shaft 135 has itsends jcurnalled in side plates S8 and 39. It will be remembered thatside plates 84, 85, 88 and 89 are carried by back-up blocks 73, 75, 74and 76, and thus they move longitudinally back and forth with the blocksand other associated apparatus.

Finger shafts 135 and 136 are ganged together to oscillate insynchronism in opposite direction in order properly to actuate theseveral tucking fingers 130 carried thereby. The oscillating movement isimparted to the shafts by means of a pair of helical gears 137 and 138,the former being carried on shaft 135 and the latter on shaft 136. Theteeth on the helical gears 137 and 13S have opposite sense so that thetwo shafts 135 and 136 may be oscillated in opposite direction by meansof a single operating means.

The single operating means may take the form of a longitudinallyextending shaft 143 (at top of Fig. 1) which has its ends journallled inplates 144 and 145 carried respectively on the front and rear ends offramework 30. A sprocket 147 secured to shaft 143 near its rear endengages a chain (not shown) which oscillates the sprocket in timedrelation with the aforesaid movement of the plunger.

Helical gears 149 .and 150 are splined to shaft 143 and these gears meshwith helical gea-rs 137 and 138, respectively, carried on the transversefinger shafts 135 and 136. Splined helical gears 149 and 150 must, ofcourse, slide longitudinally along shaft 143 to maintain proper relationwith gears 137 and 138 as the latter move back and forth for box lengthadjustment.

The gears 149 and 150 are retained in a cage arrangement substantiallylike that provided for side guide adjusting gears 115. Thus, pressureplates 80 and 81 have lateral extensions 152 which carry longitudinallyextending plates 153 which in turn carry tranversely extending 4plates154. The plate 154 at the rear end of the die may be a continuation ofits counterpart plate 111 of the side guide adjustment apparatus. Thehelical gears 149 and each `bear on one side against a pressure plateextension 152, and a sleeve 155 extends between the opposite side of thegear and a transversely extending plate 154.

The transversely extending plates 154, as in the case of plates 111 onthe opposite side of the die, have apertures which pass oscillatingshaft 143 (counterpart of side guide adjusting shaft 104), main shaft 33and countershaft 53. These plates 154, therefore, cooperate withpressure plates 80 and 81 to provide cage arrangements which continesthe back-up blocks 73-74 and their associated nuts 43-44 and take-upsprockets 60; The aforesaid elements thus maintain proper relationshipas they travel longitudinally along main shaft 33 and countershaft 53.

(e) Remaining elements for moving pressure plates 80 and 81 under highpressure As previously mentioned, one important function of the presentdie is to apply extremely high adhesive-setting pressure to the boxends. The higher the pressure, the shorter may be the time of pressureapplication. When only a short time is required, as is possible withthis invention, the productivity rate of the die may be extremely high.

The high pressure is applied by pressure plates 80 and 81 which arecaused to travel toward each other when the plunger is at lowermostposition in the second of the two strokes necessary in the manufactureof a box.

erases This high pressure movement of pressure plates 80and 81 isproduced by rotating main shafts 33 and 34 through a portion of arevolution, the main shaftnuts 43, 44, 45 and 46 being at that timerestrained against rotation. Following movement of pressure plates 80and 81 toward each other they are moved away from each other through thesame distance. Thus, these two movements may be accomplished byoscillating the main shafts 33 and 34 in synchronism, the oscillations,of course, being in timed relation with the second stroke of theplunger.

Various means may be provided to oscillate main shafts 33 and 34 insynchronism. With the threads of the main shafts as indicated at 37, 38,39 and 40, it is preferred to utilize a toggle-joint arrangement foroscillating the two shafts. Such an arrangement has a highly desirablemechanical advantage which cooperates with the mechanical advantageatorded by the threaded main shafts to develop extremely high pressure.One form of togglejoint arrangement is shown in plan view in Fig. 1, inside elevation in Fig. 2 and in end elevation in Fig. 8, the latterbeing a sectional view on line 8 8 of Fig. l.

Referring to Figs. 1 and 8, shafts 33 and 34 each are provided with acrank arm 160. These crankarms, of course, are keyed to the respectiveshafts.

A toggle-joint 162 has toggle-links 163 pivoted at their free ends tothe crank arms 160, as shown at 164. The opposite ends of toggle-links163 are pivoted together at a common pivot 165.

Suitable means are provided to reciprocate pivot 165 so as to oscillatethe main shafts 33 and 34. As illustrated in Figs. 2 and 8, toggle-jointlink 167 has one end pivoted to common pivot 165 of the toggle-joint andthe other end pivoted at 168 to a crank arm 169 carried on a rotatableshaft 170. The latter, of course, is rotated in properly timed relationwith the second plunger stroke.

Referring to Figs. 1 and 2, the forward ends of shafts 33 and 34respectively carry double sprockets 173 and 174. These double sprocketsare keyed to the shafts as shown in Fig. 2 and they may be referred toas coordinating sprockets since they cooperate to insure that mainshafts 33 and 34 oscillate in opposite directions in exactly equalamount.

Referring to Fig. 1, each pair of transversely aligned sprockets of thedouble sprockets 173 and 174 are connected by a length of sprocketengaging chain. Thus, chain 176 connects the left hand (Fig. l)transversely aligned sprockets and chain 177 connects the right handaligned sprockets. The end of each chain wraps around a portion only ofits associated sprocket and the two chains are so arranged on thesprockets that they cross at a point midway between the double sprockets173 and 174. The referred to crossing of the chains is such that itwould be observed by looking at the chains from the left end of Fig. l.

As will be understood, chains 176 and 177 provide a connection betweenmain shafts 33 and 34 which insures that the illustrated toggle-jointwill oscillate the two shafts in opposite directions through angles ofexactly equal amplitude, a condition necessary for proper pressureapplication.

Generally speaking, the various gears in the box length adjustmentsystem usually provide enough friction to lock the adjustment againstchange due to the pressures exerted by the above described high pressuresystem. However, it sometimes is desirable to provide a separate lockarrangement for example on countershaft 54 (Figs. 1, 2 and 4) to insurethat no creep occurs in the box length adjustment.

Such a lock arrangement may take the form of an apertured plate 178secured to frame 30. End 58 of countershaft 54 passes through theaperture. Plate 178 has a slit 178a (Fig. 4) extending between a pointon the periphery and the aperture, and a screw 179 is threaded into theplate and across the slit. ened to clamp the plate on countershaft end58 to thus lock the shaft against creep.

Screw 179 is tight- (f) The verticallyY movable plunger The previouslyreferred to plunger is not, strictly speaking, a part of the presentdie. Rather, it is an 'element with which the die cooperates informingboxes, as heretofore described.

A simple plunger is illustrated in dotted lines at the center of Fig.'1. Generally speaking, Iplunger 180 has an exterior size and shapewhich corresponds with the interior size and shape of the box for whichthe plunger is designed. Plunger 180 also is shown in dotted outline inFig. 2.

Plunger 180 (Fig. 2) has an upstanding portion 181 which is detachablysecured as by bolts 182 to an arm 183 mounted for up and down movement.The means for slidably mounting arm 183 for up and down movement andimparting such movement thereto in timed relation with the box makingoperation are beyond the scope of this invention and hence no furtherdetail is given.

It should be noted, however, that a plunger 180 is a simple andinexpensive element and it is easily attached to and detached from itsarm 183. These factors are of importance inasmuch as the plunger is theonly change part required by the present die yin making boxes ofdifferent sizes.

(g) Suction means for holding box bottom Referring to Figs. l and 2, apair of spaced suction cups 185 and 186 are mounted below the die withtheir effective surfaces lying in a common plane. As shown in Fig. 2,suction cups 185 and 186 should be adjusted vertically so that theaforesaid plane is parallel to and closely adjacent the plane of theplunger bottom when the plunger is in lowermost position. To accommodateplungers of different dimensions, vertical adjustment for the suctioncups may be provided.

As shown in Figs-1 and 2, suction cups 185 and 186 are laterally spacedlongitudinally of the die. If desired, means 191 may be provided to varythis longitudinal spacing in accordance with different box lengths.

Suction cups 185 and 186 are energized and deenergized through tubularconnections 195 and 196 with a suction source (not shown) which in turnis energized and deenergized in timed relation with machine operation.

As previously mentioned, the suction cups 185 and 186 are energized whenplunger 180 reaches its lowermost position in its first stroke of asingle box making operation, the suction cups then being effective tohold the box bottom in the plane of the suction cups when the plungerrises to permit formation of the double layer end Walls. The suctioncups are deenergized thereafter so that the completed box may rise withthe plunger as the latter completes its second stroke of the box makingoperation.

It will be observed from the foregoing description that a die embodyingthis invention is free of heavy castings or other rigid structure whichheretofore has been used in connection with developing high pressuresand obtaining proper alignment of bearings.' Such castings or structure,as previously mentioned, are subject to harm in the event that two boxblanks accidentally are fed simultaneously into the die. Thesuper-stresses developed in the present die on such an occurrence areopposed by the extremely high tensile strength of main shafts 33 and 34which may be of high quality steel. Thus, the chance of damage resultingfrom the operation of the die on two box blanks is virtually negligible.

If during a run of boxes it is found that the adhesive is not properlyset, as evidenced by completed boxes which open up, a slight adjustmentof the pressure plates toward each other can be made even while themachine is in operation. Such an adjustment will provide an increase inthe applied adhesive-setting pressure.

From the above description it is thought that the construction andadvantages of the invention will be Y l 11 readily apparent to thoseskilled in the art. Various changes in detail may be made withoutdepartingfrom the spirit or losing the advantages of the invention.

Having thus described my invention,` what I claim as new and desire tosecure by Letters Patent is:

l. A box making die comprising a supporting framework, a pair oflaterally spaced main shafts extending longitudinally of and journalledon said framework, each main shaft being threaded on opposite endportions with threads of opposite hand, a nut threaded on each endportion of each main shaft, front and rear pressure plates mounted totravel longitudinally with said nuts, means rotating said nuts forvarying the distance between pressure plates to provide box lengthadjustment, a crank arm carried on each main shaft, a toggle-jointlocated generally between said main shafts and having links pivotedrespectively to said crank arms and to each other, means reciprocatingthe pivot common to said links whereby said main shafts oscillate insynchro nism through a small angle in oposite directions to move saidpressure plates toward and away from each other under substantialpressure, and means coordinating the rotation of said main shaftscomprising double sprockets fixed one on each of the two main shafts,said double sprockets being in lateral alignment., and av pair of 25sprocket engaging chains cooperating with said double sprockets, eachchain having its ends wrapped around a portion only ofthe engagedsprockets, the chains being so arranged on the sprockets that they crossat a point midway between saiddouble sprockets.

2. Ina box making die having a pair of laterally spaced main` shaftsrotatable in opposite direction to develop self-equalizing box-formingpressure, the cornbination therewith of means for rotating said mainshafts comprising a crank arm carried on each main shaft, a toggle-jointlocated between said main shafts and having links pivoted respectivelyto said crank arms and to each other, a crank driven member pivoted tothe common connection vof said links, and` means coordinating therotation of said main shafts comprising double sprockets ixed one oneach ofthe two main shafts, said double sprockets being in lateralalignment, and a pair of sprocket engaging chains cooperating with saiddouble sprockets, each chain having its ends wrapped around a portiononly of the engaged sprockets, the chains being so arranged on thesprockets that they cross at a point midway between said doublesprockets.

References Cited in the tile of this patent UNITED STATES PATENTS

